You can put this solution on YOUR website! Assuming that both numbers are in base 3, find the product of 21 x 21.
21 = 2*3+1 = 7
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7*7 = 49 = 3^3 + 2*3^2 + 3 + 1
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So the answer is base 3 is 1211
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Cheers,
Stan H.